题目内容


7.Although the causes of cancer ____， we do not yet have any practical way to prevent it.  
A．are being uncoveredB．have been uncovering
C．are uncoveringD．have uncovered
A
分析语境逻辑不难发现，该空表示“现在正在被揭示”，应填现在进行时被动语态动词形式are being uncovered。
练习册系列答案
相关题目
–Excuse me, Madame. Is this plane __________ take off soon?
–Oh, yes. In five minutes.
A．about toB．starting toC．beginning toD．to
“The moment ________ soon”，he thought to himself，waiting nervously.(2012·湖南)
A．cameB．has come
C．was comingD．is coming
The College Entrance Examination________near, so you should be prepared for it.
A．is drawingB．drawsC．drewD．has drawn

Since 1 won the big prize，my telephone hasn’t stopped ringing. People____to ask how I am going to spend the money.
A．phoneB．will phone
C．were phoningD．are phoning
—Can you tell me if Tom has finished his homework?
—I've no idea. He ________ it this morning.
A．has being doingB．had done
C．is doingD．was doing
— Oh, fantastic! What is your comment on the song Jingubang?
— Terribly sorry! I _____.
A．didn’t listenB．wasn’t listening
C．haven’t listenedD．hadn’t listened
I feel so excited！At this time tomorrow morning I ________ to Shanghai.(2012·辽宁)
A．will be flyingB．will fly
C．have been flyingD．have flown
They ______Hong Kong twice.　　
A．have gone toB．have been to C．have been inD．have gone in

违法和不良信息举报电话：027-86699610 举报邮箱：58377363@163.com

精英家教网